Internal combustion engines have been known that operate on a single double-acting piston moving back and forth in a single cylinder. Such pistons are called "floating pistons" or "free pistons" although such pistons are generally fixed to a piston rod which extends outwardly from the cylinder to connect to mechanisms that can convert the linear force of the piston rod into useful energy.
In some instances there are three pistons and cylinders operating on a single piston rod in such a fashion that the two outer pistons serve to compress air for combustion in the central cylinder, first on one side and then on the other side of the double-acting piston. Such engines are described in U.S. Pat. No. 2,963,008 to Waldrop; U.S. Pat. No. 3,188,805 to Gahagan; and U.S. Pat. No. 4,385,597 to Stelzer. Because of the relative sizes of the cylinders and the connections between adjacent cylinders, the associated cylinder block is unduly complicated. Furthermore, there is no provision for employing the engine to produce other types of energy than mechanical.
It is an object of this invention to provide a novel internal combustion engine. It is another object to provide an engine having a novel design of a double-acting floating piston. Still other objects will appear from the more detailed description which follows.